Increased use of computers has led to an increase in the number of patients with ocular complaints which are being grouped together as computer vision syndrome (CVS). This newfound entity, frequently mentioned in the World Wide Web and the lay press, is now being accepted in medical literature.123 The Occupational safety and health administration department of the US Govt. [OSHA] has defined CVS as a "complex of eye and vision problems that are experienced during and related to computer use; it is a repetitive strain disorder that appears to be growing rapidly, with some studies estimating that 90% of the 70 million US workers using computers for more than three hours per day experience CVS in some form."2
The visual display terminal (VDT) images are made of pixels or dots, the resolution being measured in dots per inch. Ziefle reported that the search reaction time and fixation duration increased when the resolution decreased.4 Prolonged work on computers has been associated with diminished power of accommodation, removal of near point of convergence and deviation of phoria for near.5 These changes are most likely transient.67
The computer-related vision symptoms have been divided broadly into four main categories, viz asthenopic, ocular surface related, visual and extra-ocular, by Blehm et al.8
Various studies have recommended different modalities to overcome CVS. There is a significant difference in the spectacle prescription required for focusing on a standard printed near card and focusing on the image of a typical computer screen, both at a viewing distance of 20 inches and people require special glasses.39 The presbyopes are prescribed different types and designs of glasses in place of their usual bifocals while working on a computer.10 Feigin et al. have reported beneficial effects of spectral filters.11 Comfort is more with yoked base up and base in prisms with plus lenses than with plus lenses alone.12 Some initial studies reported users' preference for general wear progressive lenses over bifocals.13 A modification, occupational progressive lenses, is now available which incorporates a large area in the top half of the lens for mid-distance viewing of the VDT and a bottom half of the lens for near distance (for keyboard, desktop, mouse).14 Antireflective coating on these glasses helps in reducing glare and the computer workers using spectral-filter (SF) spectacles were more comfortable at their work than others who were not using such glasses.11 But larger multi-center trials are still required before any blanket recommendation in their favor can be made. Long sessions without proper work breaks are associated with increased incidence of asthenopia.15 Frequent breaks are recommended from work. Looking away from the terminal at a distant object at least twice an hour was sufficient to prevent the symptoms.16
The aim of the study was to assess the knowledge, attitude and practices (KAP) prevalent in a group of the Indian ophthalmic community towards CVS. It intended to probe whether 'computer use by practitioners' induced any difference in the knowledge and practices of the ophthalmologists.
Materials and Methods
A spot survey was carried out on ophthalmologists attending the annual conference of the All India Ophthalmological Society at Bhubaneshwar in January 2005 using a structured 34-point questionnaire answered at-the-venue (Appendix 1).
Roughly 15% of the attending ophthalmologists (n=300) were randomly given the questionnaire on the spot.
The results were evaluated using t-test and X2 tests.
Out of the 300 questionnaires distributed 134 (44.67%) responded. Of these the majority (N=102) were male. The mean age of the respondents was 43.74 ± 18.90 years with a range of 26 years to 64 years.
The responding ophthalmologists were divided into two groups:
Group A: All the ophthalmologists who were using computers at their hospitals/offices (n=32, 23.9%).
Group B: All the ophthalmologists who were not using computers at their hospitals/offices (n=102, 76.1%).
The respondents had been in practice from 0 to 35 years with a mean of 14.91 years (SD=7.84 years).
Group A practitioners had started their ophthalmic careers more recently (mean=12.11years; SD= 7.86) compared to group B practitioners (t=-2.212;P =0.03).
All respondents (N=134) claimed that they knew about CVS as a definite clinical entity. The doctors believed that the symptoms occurred after one to 10 hours of exposure to computers (mean=3.59; SD=1.66 hours). According to them almost four hours of continuous work on a computer was safe (mean=226.08 min; SD=116.174 min).
The major symptoms reported by the ophthalmologists were: eye strain (97.8%), headache (82.1%), tiredness and burning sensation (79.1%), watering (66.4%), redness (61.2%), shoulder pain (44.0%) and neck pain (35.8%). The responses to the symptoms ascribed to CVS are summarized in Fig. 1.
Of the 104 responses available regarding the number of patients being treated every month by these practitioners, the monthly figure ranged from two to 60 with a mean of 15.93(SD=11.65).
The ophthalmologists in both Group A and Group B held similar views on the symptoms of CVS but a significantly larger proportion of ophthalmologists in Group A believed that slow focusing from distance to near and vice versa (P=0.006, X2 test), blurred vision at a distance (P=0.016, X2 test) and blepharospasm (P=0.026, X2 test) formed part of the syndrome complex as compared to their counterparts in Group B [Table 1].
The participants advised their patients to blink consciously at a rate of about 14 times per minute (mean=13.81 times per min; SD=6.90). Table 2 shows tabulated results of the different modalities of treatment preferred by ophthalmologists in this study [Fig. 2].
The trend of spectacle prescription by the ophthalmologists and their preference for special type of spectacle lenses has been depicted in Tables 3 and 4 [Fig. 3].
In this study about half of the ophthalmologists (50.7%) were not prescribing any spectacles to their patients and the majority (27.6%) among those prescribing were correcting it for distance only. The majority of doctors prescribing glasses either do not have any preference for any special type of glass (68.7%) or they do not have any idea regarding what glass is to be prescribed (8.2%).
The treatment advice given by Group A and B ophthalmologists differed significantly on the issues of artificial tears (P= 0.002, X2 test), sedatives/ anxiolytics (P= 0.04, X2 test), use of bifocals, trifocals or any spectacles (P= 0.02, X2 test), blinking more often consciously (P= 0.003, X2 test) and use of divergence exercises (P= 0.02, X2 test) [Table 5].
In this questionnaire-based spot-survey, the ophthalmologists responded that the symptoms of CVS occurred after a mean of 3.59h (SD=1.66h) of exposure to computers. In their opinion almost four hours of continuous work on a computer was considered safe (mean=226.08 min; SD=116.174 min). This duration for onset of symptoms was more than the definition given by OSHA.2 It could signify the lack of awareness on part of the ophthalmologists. However, this could be an artifact induced by the small sample size.
The symptoms reported by ophthalmologists, in decreasing order were asthenopic, ocular surface-related and extra-ocular. Eyestrain has been attributed to the changes in the following visual functions after work on a computer monitor: diminished power of accommodation, removal of the near point of convergence and deviation of phoria for near vision.6
In the present study a significantly larger proportion of Group A (71.9%) associated slow focusing with CVS than Group B ophthalmologists (40.2%) [P=0.007]. Blurred vision at a distance was reported by a significantly larger proportion (P=0.03) of Group A (46.9%) as a symptom than Group B (8.8%) ophthalmologists. Pseudomyopia has been ascribed to visual display unit (VDU) use by investigators.1718 Group A ophthalmologists reported visual symptoms more frequently than Group B. This might be due to their personal experience on computers. Blepharospasm was reported as a symptom by Group B (25.0%) and Group A (8.8%) ophthalmologists [P=0.03]. This could point to better level of awareness in Group A ophthalmologists compared to Group B. There may be some error due to recall bias also. Further studies with a larger sample size are hence indicated.
The majority of the ophthalmologists (97.8%) agreed that the main mode of treatment of CVS is artificial tears (tear substitute). Elastoviscous eye drops were found to be more effective in attenuating the sensation of discomfort than regular balanced salt solution.19 Another study reported that herbal eye drop (Itone eye drop) was significantly better than tear substitutes.20 This depicts that the majority of the ophthalmologists were treating only ocular-surface-related components of CVS. They might be using it as a placebo.20 It may also indicate ignorance of other modalities of treatment of CVS.
Spontaneous eye blink rate has been found to be significantly decreased during VDT use;1921 however, it does not affect the quality (tear break-up time) or quantity (Schirmer I test, Jones test) of the tear film, although it does exacerbate the dry eye symptoms in predisposed humans.212223 In this study the majority of doctors (87.3%) especially those using computer at office advised their patients to blink more often and consciously, about 14 times per minute (mean=13.81 times per minute; SD=6.90). Group A doctors advised conscious voluntary blinking more often than the Group B doctors. Only half of the participants prescribed glasses, most of which were corrected for distance only. Only 2% of them prescribed intermediate correction [Table 3]. This may be due to lack of a standardized protocol regarding such correction in computer users.14
Other modalities of treatment reported to be used included analgesics (12.7%), topical NSAIDs (6.7%), topical steroids (9.7%), topical cycloplegics (3.0%), topical anesthetics (0.7%), looking away from the computer screen periodically (61.2%), use of convergence exercises (33.6%), use of divergence exercises (11.2%) and sedatives/ anxiolytics (14.2%). Group A ophthalmologists were more likely to prescribe sedatives/ anxiolytics (P = 0.04, X2 test), use of divergence exercises (p= 0.02, X2 test), use of bifocals, trifocals or any spectacles (P = 0.02, X2 test) and blinking more often consciously (P = 0.003, X2 test) than Group B. While the efficacy of the first two has found no support in the literature the latter two are well documented to be of benefit.3 In spite of a better level of awareness among Group A, the irrational use of anxiolytics and sedatives could point to confusion regarding treatment modalities in the absence of firmly crystallized treatment guidelines. This may reflect abundance of information on the net, but which requires to be scientifically proved. Further studies with a larger sample size are hence indicated.
An examination tailored to meet the requirements of VDU users needs to be designed. A high index of suspicion for the condition is warranted. However, the tendency to ascribe any vague symptom to CVS must be discouraged. Computer vision syndrome is a diagnosis of exclusion today as almost everyone is working on computers. An internationally acceptable diagnosis and grading system needs to be devised for CVS. It is concluded that ophthalmologists were aware of CVS, however, there was confusion regarding the diagnosis and treatment of CVS. Those ophthalmologists who were computer users were slightly better informed as compared to their counterparts who were not using computers.
Source of Support:
Conflict of Interest:
Designation: Education: MBBS only/PG Diploma/ PG Degree/ Subspecialist Fellowship
Highest Qualification: Do you routinely work on computer at office: Yes/No
If yes then specify the nature of work: Software/accounting/data retrieval/data entry/ mail only/php
How many hours every day on an average?
- Last month
- Last week
- In general
Since when have you been exposed to computers regularly?
- For Years months
- Since 199 /200
Do you know about computer vision syndrome? Yes/ No
If yes, it occurs after _____hours of computer work 1 =yes; 2=no; 3=do not know
Typical symptoms of computer vision syndrome include:
- Eyestrain 1 2 3
- Headaches 1 2 3
- Slow focusing 1 2 3
- Tired, burning eyes 1 2 3
- Neck and shoulder pain 1 2 3
- Blurred vision at distance 1 2 3
- Neck pains 1 2 3
- Colored haloes around light 1 2 3
- Mobile floaters 1 2 3
- Flashes of light before eyes 1 2 3
- Redness 1 2 3
- Watering 1 2 3
- Photophobia 1 2 3
- Blepharospasm 1 2 3
How many patients with such symptoms do you treat in a month?
What treatment do you normally prescribe to such patients? Please encircle the appropriate responses.
- Topical lubricant eye drops 1 2 3
- Analgesics 1 2 3
- Oral NSAIDs 1 2 3
- Topical NSAIDs 1 2 3
- Topical cycloplegics 1 2 3
- Topical anesthetics 1 2 3
- Topical antibiotics 1 2 3
- Spectacles: - bifocals/trifocals/progressive lenses 1 2 3
- Any special lenses you prefer to use: glass without antireflective coating/CR 39 without antireflective coating/ hard progressive adds without antireflective coating/soft progressive adds without antireflective coating/glass with antireflective coating/CR 39 with antireflective coating/ hard progressive adds with antireflective coating/soft progressive adds with antireflective coating 1 2 3
- I usually ask the patient to blink more often. 1 2 3
- How often 1 2 3
- I usually ask the patient to look away from computer screen. 1 2 3
- Once in _____ hours ____ minutes
- Convergence exercises are useful Yes/ No
- Divergence exercises are useful Yes/ No
How many hours of continuous computer work is safe?
After how much time do you prescribe a break from continuous computer work? ______Hours ______minutes.
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